saving a 1980 KZ750 twin

I forgot I had these lol

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Those look nice.

Im planning out my header design and want to run over it here for my own clarity and to get the opinions of some knowledgeable folks here.
Its going to be a stock motor with the stock carbs and airbox. (for the time being)

The stock header ID is 1.28" Since i figure this is probably the optimal size for good velocity I didn't want to go bigger but the tube i have found comes in 1.5" with a .065 wall which puts me at 1.37" ID this is only 0.1" diameter increase so it shouldn't effect it much but will probably move the powerband up slightly in the RPM range.

From what I understand it is good to have a larger exhaust diameter than exhaust port to create a step to help prevent reversion. The exhaust port is 1.37". I don't want to go bigger because it would kill the exhaust velocity, so i have been scheming on ways to help prevent reversion. I put a internal chamfer on my spigots to mimic the factory header design where the two tubes are welded together. I figure a small step like this may help with reversion.
I have also been reading about anti-reversion inserts and am contemplating adding them. Does anyone have any experience with them? i have read about them over at the XS650 forums and a guy that races one swears by them. Apparently they don't significantly increase power but help with throttle response and torque.
Im asking this because it will change how I design the exhaust flanges. If i do the anti-reversion inserts the exhaust collar will have to fit on from the head side and use a ring to hold the exhaust in place much like the factory. If i don't use the AR inserts the collars will simply slide on from the collector end. I drew up a cutaway real quick to show what I mean.

Thoughts?
 

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Got a start on the exhaust collars.
 

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Man, cant believe you machined those exhaust flanges from billet stainless. That shows extreme patience and dedication! They look wicked.
 
JadusMotorcycleParts said:
Man, cant believe you machined those exhaust flanges from billet stainless. That shows extreme patience and dedication! They look wicked.

You can't believe it because its actually aluminum. I might be stupid, but not crazy enough to do this in stainless.
 
Got the retaining rings turnt
 

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Exhaust flanges are nearly done. Had some fun on the rotary vise, also thinned them a bit and sank the retaining ring a bit deeper. No chamfer mills so I chamfered them with files. They still need a bit of polishing.
 

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thanks fellas. this is just a junk head to test fitment, I'm planning on using some stainless cap screws :D
 
These are what I buy for headers mm8 12 points... the machined head is freakishly similar to your flange

4 for $12.** just what the Doc tor ordered :eek:
http://www.ebay.com/itm/261499124624
 
Tune-A-Fish said:
These are what I buy for headers mm8 12 points... the machined head is freakishly similar to your flange

4 for $12.** just what the Doc tor ordered :eek:
http://www.ebay.com/itm/261499124624
Kinda funny when sales people talk about ti, highest grade means most brittle-hard iirc? From what i recall a scale of 1-8 where 8 is the hardest ti alloy. Oh well, no normal people ever think about these things so why should i, a mere lowly welder be concerned with it?
 
datadavid said:
Kinda funny when sales people talk about ti, highest grade means most brittle-hard iirc? From what i recall a scale of 1-8 where 8 is the hardest ti alloy. Oh well, no normal people ever think about these things so why should i, a mere lowly welder be concerned with it?

Nah... Shit does seize up in aluminum so you do need to use the supplied anti seize
 
Tune-A-Fish said:
Nah... Shit does seize up in aluminum so you do need to use the supplied anti seize
Thats why i like using studs and nuts in that particular application! Was talking about ti alloy grades though.. :)
exhaust flanges on my old trumpet i just glued on with hi temp jb will see how long that holds up, nothing like these sweet bits i reckon.
 
I started the footpeg brackets over. I want to check fitment before I proceed further. I'm no machinist, and a lot of eye balling was going on here, so these are less than perfect, but when I brush them I will remove inconsistencies and they will look pretty good
 

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Shit I didn't realize it was a race :p more of a tortoise guy anyway.
 
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